Brutalism is one of the few architectural style labels to have originally been used positively but subsequently become a term of abuse, in the process performing the opposite etymological journey to such terms as ‘gothic’and ‘baroque’.‘It is a concrete brutalist monstrosity’ is a blanket response that obscures the variety, beauty and complexity of a whole period of architecture. Barnabas Calder, who good-naturedly recalls how an architect once told him he risked becoming a ‘concrete-sniffing wanker’, has written an ebullient and gushing love letter to the style.